I created the app 3dweapons for Android about 2 1/2 years ago. (http://www.3dweapons.net) The free version was downloaded >1.7 million times. The paid version around 8k times.

I added adds from multiple sources (mopub, admob etc) and in app purchases.

For the paid app: In the top months (2 years ago) I made around 800 euro. But it dropped to 90 euro per month currently. For in app purchases: I am making 30 euro per month currently. For ads: Making about 200 euro per month currently.